| 摘要 |
A display apparatus includes a scanning assembly that scans about two or more axes, typically in a raster pattern. A plurality of light sources emit light from spaced apart locations toward the scanning assembly such that the scanning assembly simultaneously scans more than one of the beams. The scanning assembly is a resonant scanning assembly with a variable resonant frequency. The resonant frequency of the scanning assembly can be actively controlled by controlling partial pressure of fluids in a package containing the scanning assembly. In one embodiment, the increased partial pressure increases the mass of a scanning mirror, thereby changing the resonant frequency. In another embodiment, a gas absorbing material is coupled to a support arm that carries a scanning mirror. As the gas absorbing material absorbs gas, its physical properties change, thereby shifting the resonant frequency of the scanning assembly. Monitoring the resonant frequency relative to a desired frequency provides in error signal that can be used to frequency lock the resonant scanning assembly to an input signal.
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